package org.samith.web.helper;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class DigestAlgorithm {
	
	public static String getSHA1Digest(String text) {
		MessageDigest md = null;
		try {
			md = MessageDigest.getInstance("SHA-1");
		} catch (NoSuchAlgorithmException e) {
			System.out.println("===== No such Algorithm ======");
		}
		byte[] sha1hash = new byte[40];
		try {
			md.update(text.getBytes("iso-8859-1"), 0, text.length());
		} catch (UnsupportedEncodingException e) {
			System.out.println("===== Unsupported encoding exception ======");
		}
		sha1hash = md.digest();
		return convToHex(sha1hash);
	}

	private static String convToHex(byte[] data) {
		StringBuilder buf = new StringBuilder();
		for (int i = 0; i < data.length; i++) {
			int halfbyte = (data[i] >>> 4) & 0x0F;
			int two_halfs = 0;
			do {
				if ((0 <= halfbyte) && (halfbyte <= 9))
					buf.append((char) ('0' + halfbyte));
				else
					buf.append((char) ('a' + (halfbyte - 10)));
				halfbyte = data[i] & 0x0F;
			} while (two_halfs++ < 1);
		}
		return buf.toString();
	}
}
